WSJT-X Drift calculation

This is a quick program to calculate average time delta to see how closely your machine's clock matches to ham transmitters using JT65, JT9 or FT8 modes. It uses the WSJT-X DT field for this calculation, which is the time delta in seconds.

Usage

$ ./drift.pl ALL-sample.TXT
2017-09-21: 7293 samples; 0.46 avg, 1.5 max, -1.4 min
2017-09-22: 8170 samples; 0.44 avg, 1.5 max, -1.5 min
2017-09-23: 2070 samples; 0.44 avg, 1.5 max, -1.1 min
2017-09-26: 5947 samples; 0.44 avg, 4.0 max, -2.5 min
2017-09-27: 13352 samples; 0.42 avg, 1.5 max, -1.5 min
TOTAL: 36832 samples; 0.44 avg, 4.0 max, -2.5 min

From this output we see about ~440 ms of time delta between the local clock and the average ham transmitter.

Compare your clock to a time reference

If you have doubts about how your local clock compares to a reference time, use the ntpdate -q command to query a NTP server.

$ ntpdate -q tick.usno.navy.mil
server 192.5.41.40, stratum 1, offset 0.000606, delay 0.05931
18 Oct 11:20:07 ntpdate[1354]: adjust time server 192.5.41.40 offset 0.000606 sec

From this output, we see <1ms time delta to a reference standard.

Conclusions

Most hams have shitty NTP implementations.